14 years. That’s how long Sennheiser’s HD 650 headphones have been around, having initially served as the German audio company’s flagship pair and later just as a thoroughly enjoyable, reasonably priced set of premium cans. Today they’re finally being replaced by something even better, with Sennheiser unveiling a successor model in its new HD 660 S.

The HD 660 S are, at first glance, difficult to distinguish from the 650s. They retain the open-back design, slide-adjustable headband with two big pads, and much of the same familiar construction. These are all good things, because the HD 650s remain a paragon of good, ergonomic headphone design. The biggest aesthetic change is in the matte black and anthracite finish to the new 660 S, which wouldn’t look out of place in one of those Rolls-Royce Black Badge limos.

But the real difference in this new model is on the inside. Sennheiser has created an entirely new transducer for the HD 660 S, which is said to have lower harmonic distortion and produce an even more natural, uncolored sound. Each pair of Sennheiser 660s is hand-matched and tested so that the left and right ear cup produce near-enough identical sound (within a tight tolerance of +/- 1dB). Also significant in this update is a lowering of the impedance, down to 150 Ohm, which means you now have a better shot at powering the 660s without the need for a dedicated headphone amplifier. Should your smartphone still have a headphone jack, Sennheiser believes it will be able to power its new cans. They’re still best served by a nice high-end audio system, but the fact you don’t need it to listen to them is helpful in making the 660s more versatile than the 650s.

The Sennheiser HD 660 S are going to be available to buy right away, priced at $499.95 in the United States or £429.99 in the UK.